In the operation of television receivers, it is often desirable to provide some standby operating power to portions of the receiver even when the receiver is turned "off". This is particularly advantageous for permitting what has become known as "instant-on" operation of a receiver. For such a receiver when the main on/off switch is turned on, the cathode ray tube produces a picture almost instantaneously compared to the relatively long warm up time for the cathode ray tube of receivers without such "instant-on" provisions. With the advent of solid state components in the rest of the receiver, this becomes even more noticeable since the sound generally is available instantly even though some several seconds take place before the cathode ray tube produces a picture.
Integrated circuits also are being used in greater numbers in television receivers. It has been found that the operating life of such integrated circuits can be extended if they are not subjected to the extreme temperature cycling caused by turning them completely off and then turning them back on again when the operation of the receiver is desired. If a lowered standby voltage is supplied to the integrated circuits, they can be maintained in a standby operative state but at a much lower voltage level than when the receiver is in its normal "on" state of operation. This prevents the wide temperature cycling of the integrated circuits which otherwise takes place when they are turned completely off for periods of non-use of the receiver. Temperature cycling has been found to be a major cause of failure of integrated circuits; so that the application of standby power to these circuits at all times, even when the receiver is not being used or is off, is desirable.
It is not necessary, however, to provide standby operating potential to all portions of a television receiver when it is not being used but only for certain portions which include integrated circuits for processing signals and for providing filament voltage to the cathode ray tube to permit an "instant on" operation for the receiver. As a result, it is desirable to employ an on/off switching arrangement in the receiver which operates on portions of the receiver to supply a reduced standby potential to those portions while at the same time turning off other portions of the receiver in the conventional manner.